Jessica Georgenton planned to visit Vietnam, but fears of war and a mystery disease sent her to Hawaii instead. Elizabeth Wands' backpacking trip across Europe is on hold because of her parents' anxiety.

Concerns about terrorism and war are forcing thousands of Americans to change their spring vacations, with many tweaking travel plans at the last minute in favor of destinations perceived as less risky.

Many people are reluctant to head to the Middle East, but demand is also down for travel to Europe, Asia and Africa, travel agents say.

Two cruise lines, Celebrity and Princess, have completely pulled their Mediterranean packages. Airlines are waiving penalties for changing or canceling flights for the next several weeks. On Thursday, Northwest Airlines suspended its daily nonstop service from Amsterdam to India through Sunday, citing the start of military action. And American Airlines plans to cut international flights by 6 percent in April because of the effect the war is having on bookings.

The unease also extends to domestic travel. Some people are choosing to drive, rather than fly, on shorter trips and cancel others — especially to New York and Washington.

"A lot of business people who have to fly are flying, but those in discretionary travel are delaying," said Matt Bennett, publisher of FirstClassFlyer.com, a guide for business travelers. "If people are afraid, we tell them not to fly. There's no reason to fly scared."

Bill Moore, a businessman based in San Diego, canceled a flight to a board meeting in New York next week and decided to participate in the conference via the Internet.

"It was a request from my family," he said. "Being in New York, based on historical events, my family felt a little uneasy."

Recreational travelers are also focusing on destinations that make them feel safe.

"People pick the U.S. and the Caribbean because they think they are safety zones," said Aimee Ricca, owner of Bonne Amie Travel & Dreamtime Journeys USA in Rockport, Maine. "We've had a lot of Disney trips, because people view that as the ultimate safe place."

Not everyone is convinced Disney World is safe, however.

Julie Silver of Ft. Lauderdale, Fla., canceled a road trip to Disney World this weekend and plans instead to drive her 5 and 8-year-old to Universal Studios, which she views as less high-profile and, therefore, a less likely terrorist target.

Silver's concerns over air travel also have delayed her plans to see family in New York.

"I try not to be paranoid," she said. "You try to think there's a greater chance of being hit by a bus, but it still makes you nervous. That apprehensiveness, it's not worth it."

John Havard, who flew Wednesday with his wife and daughter from Seattle to Albany, N.Y., couldn't help but worry. "It's not the best day to be flying across the country. It's spooky stuff."

The threat of war prompted Wands to delay a European backpacking trip planned to celebrate her college graduation.

"My parents are worried about it," said Wands, a senior at the University of Georgia. "We haven't booked the plane tickets ... They won't let me go if the war is still going on."

For Georgenton and her aunt, it was the world situation and reports of a deadly respiratory illness in the Far East that made Vietnam a less attractive destination.

"We felt much safer being in Hawaii than overseas," she said. "It's partly the war, and the unsettling feeling of being away from family at this time. We wanted to be mellow and rather deal with the war issue from there than be bombarded by it every day from the news."

Many business travelers don't have much choice about travel.

"What are you going to do?" said Peter Shankman, a New York-based public relations agent who will take nine flights in eight days this month for business trips.

Shankman, who watched the World Trade Center burn while landing in Newark, N.J., on Sept. 11, said he is not afraid to fly.

"I feel secure on an airplane. I think it's the safest place to be," he said while preparing to fly out of New Orleans. "The one thing the 9-11 hijackers did was ruin hijacking as an industry. Airline travel is more safe now than it ever was."